PI errors....recopy dvd to high quality dvd, did I lose data

[wipeout]

I have some CMC dvd that show high PI errors...not too bad on pi failures. The disks do play fine on my dvd players...no problem

Now if I recopy to a high quality DVD...the pi errors are not on the new disk. nero supports this....

Now, is the data that got burned to the low quality dvd still the same on the new DVD....(assuming no bad sectors on disk). Thus, burning on a low quality DVD does not cause the bits of data to be soften or blurry?

I want to recopy the CMC to the high quality dvd brands...but not if the data has be roughed upped when burned under the CMS....sort of like making a copy of VHS to VHS to VHS.....do i lose anything...

[joeg04]

If you want to be sure that every bit on the new DVD is O.K., first copy the VIDEO_TS folder to your hard disk, using Windows copy/paste, or if that doesn't work use ISOBuster. Then burn your new DVD from this folder on the HDD as DVD Video. I would not use Nero for doing the copy from DVD to DVD because I'm not sure how Nero treats read errors and if it eventually would ignore read errors and copy wrong bits.

[BetaMaster]

The wonderful thing about digital copies - no generational loss

When you copy analog to analog (or analog to digital), there is always some signal loss. With one copy it's hardly noticable, but copy a copy of a copy of a copy of a copy, and the tape will be barely watchable. In the bad old days of tape mastering, a single editing error on a master tape for duplication meant you had to go back to the original source material and re-edit the entire tape from scratch - otherwise the signal loss from making an edit from the master would be noticeable to an audience.

However, PI/PO errors don't affect the data on the disc - they just affect the error correction rate, the computer's ability to "work out" the correct data that is supposed to be on the disc. If the number of errors is too high (usually over 256 in a single sector), you can lose data - the data might be all there, but the computer can't confirm that it has been correctly read. On a data disc, you get a CRC (Cyclic Redundancy Check - a primitive error checking device). On a movie, you get a skip or freeze. All CD's and DVD's (including commercial ones) have parity codes entered in with the data you want to get back out of the disc. Essentially, the reader reads the data and parity codes, and the parity codes automatically reproduce the correct data for playback (as long as there aren't too many errors). That way, you don't need all the data or all the parity codes to make a perfect copy. One, two or even a hundred PI errors in a sector still allow the reader to recover the data perfectly.

When you burn a DVD, you burn new parity codes back along with the original data. As long as a disc is fully readable (doesn't have fatally uncorrectable errors) it can be reproduced perfectly, no matter what generation copy you make.